1. Field of the Invention
The present invention relates to an ink, for ink jet recording, which can form a high-quality print having no significant bleeding or feathering on plain paper, recycled paper, or coat paper.
2. Background Art
Ink jet recording is a recording method wherein an ink is ejected as small droplets through a fine nozzle and deposited onto the surface of a recording medium to record letters or figures on the recording medium. An ink used in such ink jet recording is required to have properties including the formation of a record having a good drying property and free from bleeding or feathering and uniform recording on the surface of recording media irrespective of the type of the recording media.
What is to be noted here as a problem associated with the above properties is that, when paper is used as the recording medium, a difference in penetration of an ink between fibers constituting the paper is likely to cause bleeding or feathering. The problem of bleeding or feathering is more significant on the recycled paper which, in recent years, has become extensively used from the viewpoint of environmental problems. This is because the recycled paper is an aggregate of various paper components different from one another in rate of ink penetration. The bleeding or feathering due to the difference in penetration rate.
Various ink compositions have hitherto been proposed in order to prevent bleeding or feathering.
For example, Japanese Patent Publication No 2907/1990 proposes the utilization of a glycol ether as a wetting agent, Japanese Patent Publication No. 15542/1989 proposes the utilization of a water-soluble organic solvent, and Japanese Patent Publication No. 3837/1990 proposes the utilization of a dye dissolution accelerator. U.S. Pat. No. 5,156,675 proposes the addition of diethylene glycol monobutyl ether in order to improve the penetration of the ink, U.S. Pat. No. 5,183,502 proposes the addition of Surfynol 465 as an acetylene glycol surfactant, and U.S. Pat. No. 5,196,056 proposes the addition of both diethylene glycol monobutyl ether and Surfynol 465. In this connection, it should be noted that diethylene glycol mono-n-butyl ether is known also as "butyl carbitol" and described in, for example, U.S. Pat. No. 3,291,580. Further, the use of diethylene glycol ether has been studied in U.S. Pat. No. 2,083,372. Further, Japanese Patent Laid-Open No. 147861/1981 proposes the combined use of a pigment and triethylene glycol monomethyl ether.
Furthermore, heating of recording paper has been studied for reducing the bleeding or feathering. Heating of recording paper at the time of recording poses problems including that much time is necessary in order to raise the temperature of a heating section in the recording apparatus to a predetermined temperature. Moreover, the power consumption of the body of the recording apparatus is increased. Sometimes, recording media, such as recording paper, are damaged by the heat.
In the case of inks using a pigment, methyl ethers as disclosed in Japanese Patent Laid-Open No. 147861/1981 are, in many cases, used as the glycol ethers for inhibiting the penetration of the ink.
However, a need still exits for an ink composition which can realize a high-quality image having no significant bleeding or feathering.
An ink composition comprising a combination of a pigment with a butyl ether of a glycol, such as diethylene glycol monobutyl ether, has not been proposed in the art, so far as the present inventors know.